/*
 * $Id: PDFObject.java,v 1.3 2007/09/22 12:48:16 gil1 Exp $ $Date: 2007/09/22
 * 12:48:16 $ This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of the License,
 * or (at your option) any later version. This library is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 * the GNU Lesser General Public License for more details. You should have
 * received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place, Suite 330, Boston, MA 02111-1307 USA
 */
package pdf.handler;

import java.io.IOException;
import java.io.OutputStream;
import java.io.Serializable;
import java.util.Vector;

/**
 * This is the base class for all Objects that form the PDF document.
 * 
 * @author Peter T Mount, http://www.retep.org.uk/pdf/
 * @author Eric Z. Beard, ericzbeard@hotmail.com
 * @version $Revision: 1.3 $, $Date: 2007/09/22 12:48:16 $
 */
public abstract class PDFObject implements Serializable
{

   /*
    * NOTE: The original class is the work of Peter T. Mount, who released it
    * in the uk.org.retep.pdf package. It was modified by Eric Z. Beard as
    * follows: The package name was changed to gnu.pdf. The formatting was
    * changed a little bit. It is still licensed under the LGPL.
    */

   /**
    * 
    */
   private static final long serialVersionUID = 1L;

   /**
    * This utility method returns a String containing an array definition based
    * on a Vector containing PDFObjects
    * 
    * @param v
    *            Vector containing PDFObjects
    * @return String containing a PDF array
    */
   public static String toArray(Vector<? extends PDFObject> v)
   {
      if (v.size() == 0)
         return "";

      StringBuffer b = new StringBuffer();
      String bs = "[";
      for (PDFObject x : v)
      {
         b.append(bs);
         b.append(x.toString());
         bs = " ";
      }
      b.append("]");
      return b.toString();
   }

   /**
    * This is the unique serial number for this object.
    */
   protected int objser;

   /**
    * This allows any PDF object to refer to the document being constructed.
    */
   protected PDFDocument pdfDocument;

   /**
    * This is the object's PDF Type
    */
   private String type;

   /**
    * This is usually called by extensors to this class, and sets the PDF
    * Object Type
    * 
    * @param type
    *            the PDF Object Type
    */
   public PDFObject(String type)
   {
      this.type = type;
   }

   /**
    * Returns the PDF document this object belongs to.
    * 
    * @return PDF containing this object
    */
   public final PDFDocument getPDFDocument()
   {
      return pdfDocument;
   }

   /**
    * Returns the unique serial number of this object.
    * 
    * @return Unique serial number of this object.
    */
   public final int getSerialID()
   {
      return objser;
   }

   /**
    * Returns the PDF Type of this object
    * 
    * @return The PDF Type of this object
    */
   public String getType()
   {
      return type;
   }

   /**
    * Returns the unique serial number in PDF format
    * 
    * @return the serial number in PDF format
    */
   @Override
   public String toString()
   {
      return "" + objser + " 0 R";
   }

   /**
    * <p>
    * Writes the object to the output stream. This method must be overidden.
    * </p>
    * <p>
    * <b>Note:</b> It should not write any other objects, even if they are it's
    * Kids, as they will be written by the calling routine.
    * </p>
    * 
    * @param os
    *            OutputStream to send the object to
    * @exception IOException
    *                on error
    */
   public abstract void write(OutputStream os) throws IOException;

   /**
    * The write method should call this after writing anything to the
    * OutputStream. This will send the standard footer for each object.
    * <p>
    * Note: There are a few rare cases where this method is not called.
    * 
    * @param os
    *            OutputStream to write to
    * @exception IOException
    *                on error
    */
   public final void writeEnd(OutputStream os) throws IOException
   {
      os.write(">>\nendobj\n".getBytes());
   }

   /**
    * The write method should call this before writing anything to the
    * OutputStream. This will send the standard header for each object.
    * <p>
    * Note: There are a few rare cases where this method is not called.
    * 
    * @param os
    *            OutputStream to write to
    * @exception IOException
    *                on error
    */
   public final void writeStart(OutputStream os) throws IOException
   {
      os.write(Integer.toString(objser).getBytes());
      os.write(" 0 obj\n<<\n".getBytes());
      if (type != null)
      {
         os.write("/Type ".getBytes());
         os.write(type.getBytes());
         os.write("\n".getBytes());
      }
   }
}
